In manufacturing an electronic device such as a semiconductor device, various kinds of processes are performed on a target object. Deposition is an example of the processes that are performed on the target object. Further, there is a case where sputtering is used as a kind of deposition.
In addition, a magnetic tunnel junction (MTJ) element has been developed as a kind of electronic device. In the MTJ element, an MgO layer may be used as a tunnel barrier layer. This MgO layer is generally deposited by the following process. That is to say, Mg is deposited on a target object in a sputtering apparatus having an Mg target. Subsequently, the target object is conveyed to an oxidation processing device, which is connected to the sputtering apparatus through a vacuum conveyance device. The target object is exposed to an oxidizing gas inside the oxidation processing device so that Mg is oxidized. The deposition of such an MgO layer is described, for example, in Patent Document 1 below.